How Does Inositol Compare With Metformin?


New research is starting to compare the benefits of inositol to metformin in women with PCOS. The results may surprise you!

Why do we like inositol so much? Because of the numerous health benefits it offers women with PCOS such as:
  • Improving menstrual regularity and fertility
  • Improving the way the body uses insulin
  • Lowering cholesterol levels
  • Curbing carb cravings
  • Improving egg quality
  • Reducing the risk for gestational diabetes
  • Helping with anxiety

How Does Inositol Work?

Inositols are secondary messengers. When we eat foods (mostly carbohydrates), they get converted into glucose in our blood stream. We need the glucose to enter our cells to be used for energy. When blood glucose levels rise, a signal (imagine a doorbell is rung) is sent from the cell door to the nucleus telling it to open up. However, with PCOS, the doorbell on the cell door may be defective. This means that it takes longer for the cells to open its doors to glucose resulting in higher amounts of insulin needing to be secreted. Secondary messengers acts to repair the doorbell so that the cell doors open in a timely response to glucose, resulting in less insulin needing to be secreted.

It has been suggested that women with PCOS have a problem converting myo into DCI (myo inositol gets converted into DCI when needed to maintain a 40:1 ratio in tissues). Supplementing with too much DCI (over 600 mg or more) was actually shown to negatively affect egg quality. That’s why it’s now recommended that women with PCOS supplement with both myo and DCI in a 40:1 ratio, that mimics the body’s natural physiological levels.

How Does Inositol Compare With Metformin?

Metformin has always been the go-to drug of choice for women with PCOS. The majority of women with PCOS have insulin resistance, a precursor to type 2 diabetes. Doctors figured the most popular and well-studied diabetes drug, metformin, can help PCOS too. And it does! Metformin can reduce insulin levels and perhaps reduce the risk for type 2 diabetes. Metformin can improve the regularity of some women’s menstrual cycles, helping them to conceive.

Metformin works to decrease your body’s production of glucose. In contrast, inositol works right at the cell wall to open its doors to glucose.

Since inositols are showing great results in women with PCOS (again, women with PCOS may have a defect in their ability to use inositol which could explain why so many women have insulin resistance in the first place), it’s being studied more and compared to metformin. So far (although more studies are needed), the results are in inositol’s favor.

The most recent study out this year, 128 women with PCOS took 1500 mg metformin or myo + d-chiro inositol (in a 40:1 ratio) daily for 3 months. The results: Myo + DCI showed significantly better results in weight reduction, ovulation, and pregnancy rates (46.7% vs. 11.2%) than metformin.

In a previous randomized controlled trial, 120 PCOS women trying to conceive took 1500 mg metformin vs 4 g myo + 400 mcg folic acid daily. Their results: women who took myo inositol had a better ovulation (65% vs. 50%) and pregnancy rate (30% vs. 18%) compared with the women who took metformin.

Both these studies show encouraging news for inositol being a promising first-line treatment for helping women with PCOS conceive and reduce insulin. Inositol is a good for those who can’t tolerate the side effects of metformin (inositol can also be taken with metformin for those who do tolerate it).

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